才ノ峠遺跡・西川津遺跡出土木製品の樹種調査と組織構造

Wood artifacts excavated from the remains of Sainotoge(Nara Period) and Nishikawatsu (early to middle stage of Yayoi Period) in Matsue City were examined with a light microscope to determine their anatomical features and to identify the species.
There were forty-two wood artifacts, including board-like and stick-like pieces and bottom boards of round boxes from the Sainotoge Remains, and there were twelve items, including hoes, a plow and a pounding tool from the Nishikawatsu Remains.
The artifacts from the Sainotoge Remains were shown to consist of 27 pieces of Sugi (Cryptomeria japonica), 13 pieces of Hinoki(Chamaecyparis obtusa) and one piece each of Sakaki (Cleyera japonica) and Yabu-tsubaki (Camellia japonica). There were 3 pieces of Momi (Abies firma), 5 pieces of Kashi (Quercus spp.) and one piece each of Suda-jii (Castanopsis cuspidata), Honoki (Magnolia obovata), Tsuge (Buxus microphylla) and Mizuki (Corms controversa) among the artifacts from the Nishikawatsu Remains.
Artifacts from the Sainotoge Remains were mostly made of Sugi and Hinoki, and particularly Sugi was utilized for various objects amounting to 64 percent of the total pieces. On the other hand, the artifacts from the Nishikawatsu Remains differed both with regard to uses and species and about half of them were made of Kashi(oak) and were farm tools like hoes and plows.
The state of deterioration in the wood structure of the artifacts was examined with a scanning electron microscope and information was obtained in particular on the disintegration of tracheids: in the samples showing much deterioration, the S_3 layer of tracheid walls broke down and many spiral cracks occurred along the fibrils of the S_2 layer. It was also found that the S_2 layer was more susceptible to deterioration or breakdown compared with the outer regions of the wall including the S_1 layer.